Referring to FIGS. 14 and 15, in some conventional LCD backlight apparatuses, an opening 2a is provided on an upper section of optical sheets 1 and/or a diffusing plate 2 (which will be referred to as optical members) towards either side. Locking portion 3a are provided in a frame 3 at positions corresponding to openings 2a, so that the frame can support the optical members.